Field of the Invention
The present invention relates to data management systems, data management apparatuses, methods, and storage media storing programs that perform replication.
Description of the Related Art
For setting data for network devices, such as multifunction peripherals, etc., master data may be centrally stored and managed in another information processing apparatus, such as a management server, etc., that is connected to a network. These values are synchronized with each other. When a master data value is changed on the management server, a multifunction peripheral is notified of the changed value, and a setting data value is changed on the multifunction peripheral. Similarly, when a setting data value is changed on a multifunction peripheral, a master data value is changed on the management server (Japanese Patent Laid-Open No. 2015-121989). It is also known that, in order to maintain the integrity of the master data in the management server, the managed data is backed up at any suitable timings, and is restored at any suitable timings.
Meanwhile, known is a replication system that stores a duplicate copy of the master data of the management server in another server in case a trouble occurs in the management server and the system does not work. Japanese Patent Laid-Open No. 2006-268740 describes such a replication system in which the time it takes to duplicate the master data of the management server is reduced.
Backup is to store a state at a certain time of the management server, and backup data is not regularly updated. In contrast, replication is to mirror a current state, and therefore, when the data of the management server has been updated, replication data is regularly updated. The same system may have both the backup function and the replication function.
When one apparatus that is a database or the like stores master data while another apparatus performs replication with respect to the master data, backup master data may be restored. In such a case, data for replication representing differential information that is output for replication is not generated. As a result, the master data and the data in the replication destination become asynchronous with each other, i.e., appropriate replication cannot be performed.